The use of radiotherapy to render tissue necrotic is well established, especially in treatment of tumors. A target volume in the tissue is irradiated at a multiplicity of orientations with finely collimated beams. A particular form of radiotherapy, called stereotactic radiotherapy, requires precise localization and fixation of the target tissue. It is essential to rigidly fix the target volume in space in order to ensure that the radiation beams are correctly directed to the target. However, it is difficult, impractical and sometimes impossible to rigidly fix some limbs in the human body sufficiently for precise stereotactic radiotherapy. The head is basically the only human organ wherein the bone is so close to the skin and accessible so as to permit rigorously spatially fixing the cranium to a stereotactic frame.
It is readily understood that it is quite desirable to rigidly fix other organs, such as the prostate, to permit stereotactic radiotherapy. However, the prior art does not have any method or apparatus for spatially fixing the prostate.